Photographic film with antihalation coating



Oct. 25, 1932. ALM v 1,884,035

FHOTOGRAPHIC FILM WITH ANTIHALATION COATING Fi1ed Feb. 20, 1952 Z SENSITIVE LAYER lSl/PPORT 5A/vn-HALAT/o/v LAYER OF WATER SOLUBLE SALT OF A mcARBoxvL/o ACID ESTER OF CELLULOSE ANDA DYE.

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Patented Oct. 25, 1932 UNITED STATES PATENT GFFICE CARL J'. MALM, F RQCHESTER, NEW YORK, ASSIGNOR TO EASTMAN KODAK COMPANY, OF ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK Application filed February 20, 1932. Serial No. 594,261..

This invention relates to a. method of col oring sheet material and to the material so colored. It relates more specifically to the application of a color under conditions where it is later desirable that the color be completely removed, and more particularly to a layer that serves as'an anti halation backing for photographic films.

- For this purpose it is particularly desirable that the-colored layer adhere strongly to the support under ordinaryusage, that the color be uniform and that the layer be completely removed, together with all trace of color, from the support in the ordinary photographicbaths.

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The number -'of dyes available for use 18 I have discovered that the water-soluble salts of dicarboxylic acid-esters of cellulose have the desired qualities and are admirably adapted. for such use. These are described in the copending application, Serial No. 380,252, filed Jul 22, 1929,-by Charles E.

- /Varing and myself. The present application is, moreover, a specific improvement and embodiment of the invention generically claimed in the copending application of K. C. D. Hickman, Serial No. 528,266, filed April 7, 1931.

In the single figure of the accompanying drawing is a section on an enlarged scale of a film embodying my invention. As there indicated, it comprises a'support 1 of a composition including a cellulose derivative,-

such as, cellulose nitrate or cellulose acetate, a photograp'hically sensitive layer 2 on one surface of the support and, on the other surface, a layer '3 of a water soluble salt of'the class mentionedcontaining a dye or mixture of dyes useful for anti-halation purposes.

The water soluble alkali salts pf the class defined are especially useful, among those particularly recommended being sodium cellulose phthalate and the potassium and ammonium salts of cellulose acetate hydrogen phthalate -and of cellulose acetate hydrogen 7 practically unlimited. Among these may be mentioned the following: Rhodamine B; Crystal violet 6 B; Nigrosine; Bismarck brown; Tartrazine; Benzopurpurine; Congo red; Metanil yellow; Auramine,singly or in combinatio The particular dyes chosen would, of course, depend on other factors involved in connection with the fihn, its sensitivity, use

and method of processing.

The water-soluble dye may be added to a water solution of the salt, which is then spread or sprayed over the support. It would also be possible first to coat the carrier layer onthe support and then to apply analcohol soluble dye to the coated layer. I

Although proportions would depend largely on the desired properties of a particular layer, the following are given merely as exam-v v ples of formulas which have been found use-' -ful:

FormulaA:

. Parts Sodium cellulose phthalate Crystal violet 6B 4.5 Tartrazine 2 Glycerine .2 Saponin .1 Water to Formula B:

Parts Ammonium cellulose acetate hy- 8o drogen phthalate -5. 5 v Nigrosine J 4 Glycerine .1 Iso-amyl alcohol .2 Water to 100 35 A formula may be expressed in general terms as follows:

Water to 100 In the above formulae, parts are by weight. I consider as included within my invention such modifications and equivalents as are included within the scope of the following claims. Having thus described my invention, wh: t 100 I claim as new and desire to be secured 1) Letters Patent is:

1. A colored sheet comprising a support and a colored layer thereon, the colored layer com rising as a carrier material a water solu le salt of a dicarboxylic acid ester of cellulose.

2. A colored sheet comprising a support. and a removable colored layer thereon, the.

colored layer comprising as a carrier ma terial a Water soluble alkali salt of a dicarboxylic acid ester of cellulose and including a dye.

3. An anti-halation photographic film comprising a transparent support having on onesurface a sensitive emulsion and upon the other surface a colored anti-halation layer comprising a water soluble salt of a dicarboxylic acid ester of cellulose.

4. An anti-halation photographic film' comprising a transparent support of a plastic cellulosic composition having upon one surface a photographically sensitive emulsion and upon the other surface an anti-halation layer comprising a water-soluble alkali salt of a dicarboxylic acid ester of cellulose and containing a dye.

Signed at Rochester, New York, this 12th day of February, 1932. p

1 CARL J. MALM. 

